The present invention pertains to jaw crushers for stones and the like and which include stationary and swingable die plates which function as crushing surfaces. More particularly, the invention relates to means for mounting the stationary jaw die plate in such a manner that it is rigidly secured but readily removable.
Prior art jaw crushers have provided various means for retaining the stationary jaw die plate, but each of these various means have had disadvantages. For example, some of the prior art jaw crushers have provided elongated wedges or retaining plates which clampingly engage the edges of the jaw plate in order to secure it to the frame member. These means of securing the jaw plate have the disadvantage that they do not allow the plate to expand sufficiently when it undergoes expansion as a result of the peening effect of the rock being crushed. Other types of prior art crushers include bolts which extend through pockets in the die plate and which are secured to frame members as a means for supporting the die plates. Generally this method has the drawback that it is undesirable to provide pockets or bores which extend through the die plate because these bores can effect the performance of the crusher and the durability of the die plates. Furthermore, the bolts used to secure the plates are usually relatively inaccessible and removal of the plates or tightening of the bolts is generally a difficult and time consuming task. Other prior art alternative securing means have included the use of two-piece cheekplates which are used to support the opposite side edges of the stationary jaw die plate. In such securing means, one of the cheekplate pieces is secured to the frame side plates of the jaw crusher and adjacent to one of the side edges of the jaw die, and the other cheekplate piece which has a generally wedged shape is forced between the secured cheekplate piece and the edge of the jaw die plate thereby forcing the jaw die against a supporting surface. Such wedge securing means have the disadvantage that during the rock crushing operation the peening action of the rock against the cheekplates tends to lock the wedge portion so firmly in place that it cannot be removed without use of a cutting torch. Since the cheekplates are comprised of manganese steel and are rather sizable, this type of removal process destroys expensive parts and is time consuming.